Protagoras of Abdera
Protagoras of Abdera (c. 490–c. 420 BCE) was one of the most influential sophists and a central figure in the intellectual life of classical Athens. Renowned as a professional educator, he taught rhetoric, argumentation, and civic virtue to ambitious citizens for a fee, claiming to make the weaker argument appear stronger and to improve his students’ capacity for public life. His most famous dictum, preserved by Plato, is that "man is the measure of all things," often read as a radical form of epistemic and moral relativism in which truth and value depend on human perspectives rather than objective realities. Protagoras also advanced a pioneering form of agnosticism, asserting in his lost work "On the Gods" that the existence and nature of the gods are unknowable. Closely associated with Pericles, he reportedly helped frame the laws of the colony of Thurii, highlighting his practical political significance. Although his original writings survive only in fragments and hostile reports, Protagoras profoundly shaped debates on knowledge, language, education, and democracy, and became the paradigmatic sophist in the critical portraits of Plato and Aristotle.
At a Glance
- Born
- c. 490 BCE(approx.) — Abdera, Thrace
- Died
- c. 420 BCE(approx.) — Likely at sea near Sicily or along the Italian coastCause: Drowned in a shipwreck (traditional account, historically uncertain)
- Floruit
- mid-5th century BCE (c. 450–420 BCE)Conventional floruit based on reports that he was active during the career of Pericles and before the Peloponnesian War
- Active In
- Abdera (Thrace), Athens, Greek mainland poleis, Sicily
- Interests
- EpistemologyEthicsRhetoricEducation (paideia)Political theoryReligion and theologyLanguage and argumentation
Protagoras’ thought centers on the claim that all cognition and evaluation are relative to human perceivers and communities—summarized in his dictum that "man is the measure of all things"—so that truth, goodness, and even religious belief are not fixed features of an objective reality but products of human perspectives, practices, and conventions, which can nonetheless be rationally shaped and improved through skilled argument and education.
Περὶ ἀληθείας (ἢ Καταβάλλοντες λόγοι)
Composed: c. 440–430 BCE
Περὶ θεῶν
Composed: c. 440–430 BCE
Ἀντιλογίαι
Composed: mid-5th century BCE
Περὶ ἀρετῆς
Composed: mid-5th century BCE
Περὶ τῆς ἐν ἀρχῇ καταστάσεως (reconstructed title)
Composed: mid-5th century BCE
Of all things the measure is man: of the things that are, that they are; and of the things that are not, that they are not.— Plato, Theaetetus 152a, quoting Protagoras’ "Truth"
This famous fragment expresses Protagoras’ doctrine that the truth or being of things is relative to human perceivers, and serves as the starting point for Plato’s extended critique of relativism.
Concerning the gods, I am unable to know whether they exist or do not exist, nor what form they have; for there are many obstacles to knowledge, the obscurity of the matter and the shortness of human life.— Fragment from Protagoras’ "On the Gods", preserved in Diogenes Laertius, Lives of Eminent Philosophers 9.51
This passage encapsulates Protagoras’ agnostic stance toward traditional theology, emphasizing the epistemic limits that prevent humans from attaining secure knowledge about the divine.
On every matter there are two arguments opposed to one another.— Attributed to Protagoras in Diogenes Laertius, Lives of Eminent Philosophers 9.51, referring to the "Antilogies"
This maxim underlies Protagoras’ method of teaching by setting contradictory logoi against each other, training students to argue both sides and revealing the contestable nature of claims.
He made the weaker argument appear the stronger.— Aristotle, Rhetoric 1402a23–25 (characterizing Protagoras’ sophistic practice)
Aristotle reports this as a hallmark of Protagoras’ rhetorical art, illustrating both his skill in persuasion and the suspicion with which sophistic techniques were regarded by philosophers.
Protagoras used to say that he educated people to take care of their own affairs well and of the affairs of the city.— Paraphrased from Plato, Protagoras 318e–319a
In Plato’s dialogue, Protagoras defends the teachability of virtue and describes his educational mission as cultivating practical excellence in both private and public life.
Formative Years in Abdera
Growing up in Abdera, a city associated with Democritus and other intellectual currents, Protagoras is traditionally said to have begun as a porter or laborer, gradually attracting notice for his acuity in argument and language; though anecdotal, this background underscores his self-made status apart from aristocratic education.
Itinerant Sophist and Educational Innovator
As an itinerant sophist across the Greek world, Protagoras systematized and commercialized higher education, developing exercises in debate, rhetorical technique, and practical reasoning aimed at success in law courts and assemblies, while reflecting on whether virtue (aretē) can be taught.
Athenian Prominence and Political Engagement
In mid-5th century Athens, Protagoras gained the patronage of Pericles and the city’s elite; his reputed role in drafting the laws of Thurii, as well as the high fees he commanded, indicate both his prestige and the controversy surrounding sophistic professionalization of wisdom.
Philosophical Formulation of Relativism and Agnosticism
In works such as "Truth" and "On the Gods," Protagoras articulated sophisticated positions on the relativity of perception, the dependence of truth on human experience, and the limits of religious knowledge, provoking strong reactions from traditionalists and setting the agenda for later epistemological critique.
Reception in Platonic and Aristotelian Critique
After his death, Protagoras’ doctrines were preserved mainly through the critical reconstructions of Plato and Aristotle, who used him as the emblem of sophistic relativism and subjectivism; this reception simultaneously distorted and canonized his thought, ensuring his enduring place in philosophical history.
1. Introduction
Protagoras of Abdera (c. 490–c. 420 BCE) is widely regarded as one of the most influential sophists of classical Greece and a pivotal figure in the intellectual culture of democratic Athens. Operating as a professional educator who charged fees, he offered advanced paideia in rhetoric, argumentation, and civic excellence (aretē) to ambitious citizens, especially in Athens during the age of Pericles.
Ancient testimony portrays Protagoras as a systematic thinker rather than a mere rhetorician. He developed reflective positions on knowledge, perception, ethical and political norms, and religion. His most famous doctrine, transmitted by Plato, is the so‑called Measure Doctrine:
“Of all things the measure is man: of the things that are, that they are; and of the things that are not, that they are not.”
— Protagoras, Truth (fr.), in Plato, Theaetetus 152a
This dictum has typically been interpreted as a form of epistemic relativism, according to which truth and being are relative to human perceivers. Protagoras also formulated an early and striking agnostic stance regarding the gods, and he advanced techniques of antilogia, the confrontation of opposing arguments, as a central pedagogical tool.
Our knowledge of Protagoras is fragmentary and mediated almost entirely through later authors—above all Plato and Aristotle—who were often critical of sophistic methods. As a result, both his life and his doctrines are the subject of extensive scholarly reconstruction and debate. Despite these difficulties, Protagoras is commonly seen as a key representative of the so‑called Attic Enlightenment, in which established norms, religious traditions, and claims to knowledge were subjected to rigorous, publicly oriented scrutiny.
This entry surveys Protagoras’ historical context, the evidential basis for his thought, his major works and doctrines, and his reception from antiquity to modern philosophy, with particular attention to the contested interpretation of his relativism and its implications for ethics, politics, and religion.
2. Life and Historical Context
2.1 Biographical Outline
Ancient sources give only sketchy information about Protagoras’ life, and much is conjectural. He was reportedly born in Abdera in Thrace around 490 BCE and was active mainly in the mid‑5th century. Diogenes Laertius and later doxographers describe him as an itinerant sophist, traveling among Greek poleis to teach rhetoric and civic virtue for a fee.
A frequently cited, though anecdotal, tradition portrays Protagoras as having begun his career as a manual laborer or porter, later recognized for his intellectual skill. Modern scholars disagree about the reliability of this story: some see it as hostile caricature of a non‑aristocratic teacher, others as reflecting the social mobility associated with sophistic education.
2.2 Association with Athens and Pericles
Protagoras’ prominence is closely tied to Athens during its democratic and imperial peak under Pericles. Several ancient reports, especially from Plato and later writers, depict him as enjoying Pericles’ patronage and instructing members of the Athenian elite. Tradition holds that he was commissioned to help draft the laws for the colony of Thurii in southern Italy (c. 445–440 BCE), suggesting a level of political trust and practical expertise, though the exact scope of his role is uncertain.
2.3 Conflict and the Impiety Charge
Later accounts relate that Protagoras faced prosecution for impiety in Athens, prompted by the opening lines of his lost work On the Gods, and that his books were publicly burned. The historicity of a formal trial is debated: some scholars consider it plausible in the tense religious and political climate of late 5th‑century Athens; others regard it as a later embellishment reflecting general hostility to sophists. A traditional but insecure report has him drowning in a shipwreck while traveling to or from Sicily.
2.4 Historical Setting: The Attic Enlightenment
Protagoras lived in a period marked by:
| Feature | Relevance to Protagoras |
|---|---|
| Athenian democracy | Created demand for rhetorical training and civic aretē. |
| Intellectual pluralism | Coexisted with natural philosophers (e.g., Democritus) and other sophists. |
| Nomos–physis debates | Framed questions about law, convention, and nature central to his political thought. |
| Religious tension | Heightened scrutiny of traditional myth and cult, relevant to his agnosticism. |
Within this context, Protagoras appears as both a product and a leading agent of a culture in which argument, persuasion, and critical reflection became central tools of public life.
3. Sources and Historiographical Problems
3.1 Nature of the Evidence
No complete work by Protagoras survives. Knowledge of his thought derives from:
| Source Type | Examples | Characteristics |
|---|---|---|
| Platonic dialogues | Protagoras, Theaetetus | Dramatic, philosophically motivated reconstructions. |
| Aristotelian treatises | Metaphysics, Rhetoric, Sophistical Refutations | Systematic critiques, often schematic. |
| Doxographical reports | Diogenes Laertius 9.50–52; Sextus Empiricus | Brief summaries, mixed reliability. |
| Fragment collections | Verbatim or paraphrased quotations in later authors | Isolated and context‑poor. |
Modern critical editions reconstruct a small corpus of fragments and testimonia, but the authenticity and interpretation of many passages are disputed.
3.2 Platonic Mediation
Plato is the principal source for Protagoras’ doctrines, especially on the Measure Doctrine, relativism, and the teachability of virtue. However, scholars note that:
- The dialogues are dramatic works, not historical transcripts.
- Protagoras often serves as a foil for Socratic and Platonic positions.
- Plato may systematize or exaggerate Protagorean ideas to fit his philosophical aims.
Consequently, some researchers attempt to “peel back” Platonic interpretation to recover a more modest or practical Protagoras, while others maintain that Plato’s evidence, though polemical, is indispensable and broadly reliable.
3.3 Aristotelian and Later Testimony
Aristotle treats Protagoras as emblematic of relativism and sophistic argumentation, citing him in discussions of truth, contradiction, and rhetoric. Critics argue that Aristotle tends to assimilate Protagoras to a generalized picture of sophistry, possibly overstating his commitment to extreme positions (e.g., denying non‑contradiction).
Later writers—Sextus Empiricus, Cicero, Diogenes Laertius—compile varied reports. Some present Protagoras as a serious epistemological thinker; others emphasize clichés about “making the weaker argument stronger.” Historians debate how far these notices are independent or simply echo Platonic and Aristotelian portrayals.
3.4 Modern Historiographical Debates
Key controversies include:
- Extent of relativism: Is the “man‑measure” thesis a universal doctrine or limited to perception and practical judgments?
- Ethical stance: Was Protagoras a radical subjectivist, a conventionalist, or a reformist educator within democratic norms?
- Religious views: Does his agnosticism imply skepticism about all metaphysics, or only about traditional anthropomorphic gods?
Different reconstructions reflect broader methodological choices: some emphasize intellectual coherence and read Protagoras as a systematic philosopher; others stress the performative and educational aspects of sophistry. These historiographical problems shape every aspect of the modern picture of Protagoras.
4. Intellectual Development and Career as a Sophist
4.1 Formative Milieu in Abdera
Protagoras’ early life in Abdera, a city associated with Democritus and other intellectual currents, likely exposed him to a vibrant mix of pre‑Socratic natural philosophy and cosmopolitan trade culture. While direct influence from Democritus is unproven, some scholars have suggested possible parallels between Protagorean relativism and atomist accounts of perception, though others caution against speculative connections.
Anecdotes about his early work as a porter or artisan are interpreted variously as:
- Evidence of a non‑elite background in contrast to traditional aristocratic education.
- A rhetorical topos used by opponents to underscore the “parvenu” status of sophists.
4.2 Emergence as an Itinerant Sophist
By the mid‑5th century BCE, Protagoras appears as one of the first to professionalize sophistic teaching. He traveled among Greek cities, offering instruction in:
- Rhetoric and logos for court and assembly.
- Practical reasoning about civic affairs.
- The cultivation of aretē suited to democratic participation.
Reports of his high fees and the eagerness of elites to study with him suggest a market for advanced intellectual training beyond traditional gymnasium and music education.
4.3 Athenian Phase and Political Engagement
In Athens, Protagoras’ career reached its apex. Plato depicts him surrounded by admirers and in dialogue with figures such as Socrates, Alcibiades, and Callias. The reported commission to help design the law code of Thurii is interpreted as:
- For some historians, proof of his recognized expertise in law, language, and civic organization.
- For others, a possible exaggeration reflecting later admiration for his political acumen.
His activity coincided with intense debates on democracy, imperial expansion, and the role of persuasive speech, in which sophists played a prominent role as both educators and public intellectuals.
4.4 Mature Doctrinal Formulation
Protagoras’ principal works—Truth, On the Gods, Antilogies—are generally dated to his Athenian period (c. 440–430 BCE). During this phase he seems to have articulated:
- The Measure Doctrine, linking human perception and judgment to truth claims.
- A method of opposing arguments (antilogiai) as both pedagogical and theoretical.
- Sophisticated reflections on virtue’s teachability, as dramatized in Plato’s Protagoras.
Many scholars see a progression from practical rhetorical training toward more self‑conscious philosophical theorizing, though the evidence does not permit a detailed chronological development. What can be said is that Protagoras’ career exemplifies the transformation of Greek intellectual life from aristocratic wisdom to public, paid, and argumentative education.
5. Major Works and Fragments
Since none of Protagoras’ writings survive intact, modern knowledge rests on titles and brief quotations or paraphrases. The following table summarizes the main works attributed to him:
| Work (English / Greek) | Status | Main Themes (as reconstructed) |
|---|---|---|
| Truth or Refutations (Peri alētheias / Kataballontes logoi) | Fragmentary | Measure Doctrine, relativism about perception and judgment, critique of rival claims to wisdom. |
| On the Gods (Peri theōn) | Fragmentary | Agnostic stance on the existence and nature of gods, limits of human knowledge. |
| Antilogies (Antilogiai) | Fragmentary | Technique of opposing arguments, training in debate, reflection on the contestability of logoi. |
| On Virtue (Peri aretēs) | Lost; authorship disputed | Possible systematic treatment of ethical excellence and its teachability. |
| On the Original State and Society (reconstructed) | Lost; authorship disputed | Accounts of early human conditions, emergence of society, law, and political order. |
5.1 Truth (or Refutations)
Most scholars identify Plato’s quotation of the Measure Doctrine in Theaetetus as originating from Truth. The alternative title, Refutations, suggests a polemical dimension, perhaps aimed at undermining dogmatic claims by showing how contrary appearances are equally “true” for different perceivers. Debate continues about whether the work advanced a global relativism or focused on perceptual and practical judgments.
5.2 On the Gods
Preserved only in its famous opening line, On the Gods articulated Protagoras’ agnostic position:
“Concerning the gods, I am unable to know whether they exist or do not exist, nor what form they have…”
— Protagoras, On the Gods (fr.), in Diogenes Laertius 9.51
Ancient testimony links this work to the impiety charge in Athens. Scholars discuss whether the treatise simply suspended judgment or also offered critical analyses of traditional myths and cultic practices.
5.3 Antilogies
The Antilogies likely systematized Protagoras’ method of placing opposed logoi side by side. Diogenes Laertius reports the thesis that “on every matter there are two arguments opposed to one another,” interpreted as a principle of debate training and possibly as an epistemological claim about the bilateral structure of reasoning.
5.4 Disputed and Lost Treatises
Works such as On Virtue and a treatise on the original state and society are attested indirectly, especially via myths and arguments in Plato’s Protagoras. Some scholars infer that these Platonic narratives rest on genuine Protagorean texts; others regard them as Platonic constructions inspired by sophistic themes more broadly. Consequently, the existence and content of these works remain conjectural.
6. The Measure Doctrine and Relativism
6.1 The Core Fragment
The Measure Doctrine is encapsulated in the fragment:
“Of all things the measure is man: of the things that are, that they are; and of the things that are not, that they are not.”
— Protagoras, Truth (fr.), in Plato, Theaetetus 152a
Most scholars accept that this statement stands at the heart of Protagoras’ epistemology, though its precise meaning is contested.
6.2 Traditional Relativist Reading
A dominant interpretation, influenced by Plato’s Theaetetus, holds that Protagoras advocates epistemic relativism:
- Truth is relative to the individual perceiver: whatever appears to someone is true “for” that person.
- Conflicting judgments (e.g., “the wind is cold” / “the wind is not cold”) are both true, each for the respective subject.
- There is no standpoint independent of human perception from which to adjudicate between such appearances.
On this view, the Measure Doctrine implies that human beings—or even individual humans—are the final standard (metron) for what counts as real or true.
6.3 Moderate and Communal Readings
Alternative interpretations soften this individualism:
- Communal relativism: Some scholars argue that “man” (anthrōpos) should be understood as humankind or a community, so that truth is relative not to isolated individuals but to shared practices, languages, or nomoi.
- Domain‑limited relativism: Others restrict the doctrine to perceptual and evaluative claims (e.g., judgments of taste, utility, or justice as conventionally defined), leaving open the possibility of more stable truths in other domains.
These readings aim to make Protagoras’ position more coherent and less vulnerable to Plato’s objections about self‑refutation.
6.4 Measure Doctrine and Antilogies
The thesis that “on every matter there are two opposing arguments” is often taken as a complement to the Measure Doctrine. If different perspectives are each “true for” their holders, then contradictory logoi can legitimately be advanced. Protagoras’ educational practice of antilogia may thus be grounded in a theoretical view about the plurality and relativity of standpoints.
6.5 Critiques and Defenses in Antiquity
Plato and Aristotle portray the Measure Doctrine as undermining:
- Objective knowledge, since no belief is “truer” than another.
- Rational disagreement, if every appearance is equally valid.
- The principle of non‑contradiction.
Some ancient and modern interpreters, however, contend that Protagoras allowed for better and worse logoi in a pragmatic sense: arguments can be judged superior if they lead to more beneficial outcomes for individuals or cities, even if they are not “truer” in an absolute sense. This more pragmatist reading remains a focal point of contemporary debate.
7. Epistemology: Perception, Belief, and Truth
7.1 Perception as Foundation
In Plato’s Theaetetus, Socrates reconstructs Protagoras as identifying knowledge with perception (aisthēsis). On this account:
- Perceptual appearances are immediate and incorrigible for the subject.
- Differences in perception (e.g., hot/cold, sweet/bitter) are explained by differences in the interacting states of perceiver and environment.
- There is no further standard beyond these appearances to determine which is “really” correct.
Many scholars view this as a plausible extension of the Measure Doctrine, though whether Protagoras explicitly equated knowledge and perception is uncertain.
7.2 Truth “For” a Subject
The Protagorean notion that each belief is true “for” the believer has been understood as introducing indexed truth:
| Entity | Truth Condition (Protagorean reading) |
|---|---|
| Belief p of subject S | p is true‑for‑S iff S has the appearance or judgment that p. |
On this model, conflicting beliefs are not jointly true in an unqualified sense, but each holds relative to its subject. Critics argue that this collapses the distinction between appearance and reality; defenders suggest it highlights the inescapably perspectival character of human cognition.
7.3 Error and Improvement
A central issue is whether Protagoras can account for error and cognitive improvement if every belief is true for its holder. Ancient critics claimed he could not; modern interpreters have proposed several responses attributed to (or compatible with) a Protagorean stance:
- Pragmatic betterment: Beliefs may be “better” if they yield more beneficial consequences, even if not truer.
- Intra‑subject comparison: A person can move from one appearance to another that they themselves regard as more satisfying or stable.
- Communal correction: A community’s shared standards (nomoi) provide benchmarks for re‑educating individuals whose beliefs are harmful or dysfunctional.
These reconstructions aim to reconcile relativism with Protagoras’ role as an educator promising improvement.
7.4 Knowledge, Expertise, and the Sophist
Protagoras claimed to teach his pupils to “take care of their own affairs well and of the affairs of the city.” This suggests a conception of expertise not as access to objective truths but as:
- Mastery of argumentative techniques.
- Sensitivity to context and audience.
- Ability to shape beliefs and appearances in more advantageous directions.
Some scholars see here an early form of contextualist or pragmatic epistemology, while others regard it as collapsing knowledge into mere persuasion. The scarcity of direct evidence prevents a definitive resolution, but it is clear that for Protagoras, epistemic questions are tightly bound to practical success and civic life.
8. Ethics and the Teachability of Virtue
8.1 Virtue as Civic Excellence
Protagoras presented himself as a teacher of aretē—not abstract moral theory, but the excellence required for success in private and public affairs. In Plato’s Protagoras, he describes this as cultivating capacities relevant to:
- Deliberation in the assembly.
- Persuasion in law courts.
- Management of household and property.
This suggests an ethical outlook oriented toward civic participation within the democratic polis.
8.2 The Teachability Thesis
A central theme associated with Protagoras is that virtue can be taught. In contrast to views that attribute excellence to natural talent or divine favor, Protagoras emphasizes:
- The pervasive role of socialization and education in shaping character.
- The possibility of systematic instruction to refine these traits.
- The responsibility of citizens and cities to cultivate virtue.
In Plato’s dialogue, Protagoras supports this thesis with myth and argument; whether these are verbatim or Platonic elaborations, they likely reflect a core Protagorean position.
8.3 Relation to Relativism
Interpreters have debated how a relativist about truth and values can coherently teach virtue:
- On one reading, virtue is relative to civic norms (nomoi); the sophist teaches how to embody and use these norms effectively.
- On another, Protagoras is seen as a reformer, helping cities move from worse to better norms in terms of collective advantage (e.g., security, cohesion, prosperity), without invoking absolute moral standards.
In both reconstructions, ethical evaluation is closely linked to human needs and social functioning, rather than to metaphysical notions of the Good.
8.4 Unity or Plurality of Virtues
Plato’s Protagoras stages a debate over whether the virtues (justice, temperance, piety, courage, wisdom) are one or many. Protagoras there tends to treat them as distinct yet related, whereas Socrates pushes toward a unity thesis. Some scholars infer that Protagoras accepted a pluralistic conception of virtues corresponding to various social roles and contexts. Others caution that Plato may be dramatizing an opposition for his own purposes, making it difficult to ascribe a definite doctrine to Protagoras himself.
8.5 Responsibility and Accountability
Protagoras’ emphasis on teachability implies that humans are responsible for their actions: if character and conduct can be shaped through education, then praise and blame, reward and punishment, are meaningful. His projected role as a moral and civic educator thus aligns with broader sophistic efforts to ground ethical and legal responsibility in human practices rather than in divine command or fixed natural hierarchy.
9. Rhetoric, Antilogies, and Educational Practice
9.1 Rhetoric in a Democratic Polis
In 5th‑century Athens, success in assembly and law courts depended heavily on skillful speech. Protagoras capitalized on this demand by offering structured instruction in rhetoric (rhētorikē) and logos. Ancient testimonies portray him as among the first to:
- Analyze grammatical forms and types of speech.
- Offer methodical exercises in composition and delivery.
- Reflect explicitly on argument structure.
His approach integrated technical skills with broader prudential judgment about what to say, to whom, and when.
9.2 The Doctrine of Antilogies
The Antilogies articulated the principle:
“On every matter there are two arguments opposed to one another.”
— Protagoras, Antilogies (fr.), in Diogenes Laertius 9.51
This is interpreted as both:
- A pedagogical method: students practice arguing for and against the same thesis, thereby sharpening their ingenuity and adaptability.
- A theoretical claim: human affairs typically admit plausible reasons on both sides, reflecting the contestable nature of many judgments.
Ancient critics, especially Aristophanes and Plato, caricatured this as a willingness to defend any side for pay; modern scholars also emphasize its role in developing dialectical reasoning and appreciation of complexity.
9.3 “Making the Weaker Argument Stronger”
Aristotle reports that Protagoras made it his business to “make the weaker argument appear stronger.” This phrase has been variously understood:
| Interpretation | Emphasis |
|---|---|
| Cynical manipulation | Sophists as undermining justice by rhetorical trickery. |
| Forensic strategy | Strengthening legally or evidentially weaker cases in adversarial contexts. |
| Critical testing | Intensifying scrutiny by pushing weak positions to their limits. |
Some historians argue that Protagoras may have seen value in fortifying weak arguments as a way to test and refine stronger ones, anticipating later methods of systematic objection and reply.
9.4 Educational Goals and Curriculum
Protagoras’ pedagogy, as depicted in Plato and other sources, likely included:
- Memorization and analysis of poetry and prose, used to discuss moral and civic themes.
- Debate exercises based on antilogia, sometimes involving paradoxical theses.
- Training in style, clarity, and emotional appeal, tailored to political and legal audiences.
He portrayed these activities as serving the higher aim of enabling students to manage their own affairs and those of the city well, indicating that rhetorical expertise was seen as a component of practical wisdom, not a purely formal skill.
9.5 Criticisms and Defenses
Ancient critics accused sophists of:
- Prioritizing persuasion over truth.
- Encouraging relativism and moral laxity.
- Selling wisdom for money.
In response, proponents of Protagoras emphasize that his methods:
- Acknowledged the inevitable role of rhetoric in democratic decision‑making.
- Provided citizens with tools for critical evaluation of competing arguments.
- Reflected a serious engagement with the ethical and political consequences of speech.
The balance between these critical and sympathetic readings continues to shape modern assessments of his rhetorical practice.
10. Politics, Law, and the Nomos–Physis Debate
10.1 Protagoras and Democratic Politics
Protagoras’ teaching flourished in democratic Athens, where political power was exercised through deliberation and voting. His curriculum in rhetoric and civic aretē positioned him as a key participant in the shaping of democratic elites, even if he himself did not hold office. Ancient traditions that associate him with Pericles and with the foundation of Thurii suggest that he was consulted on matters of constitutional design and lawmaking, though details are uncertain.
10.2 Nomos and Physis
The 5th century BCE saw intense debates over nomos (law, custom) and physis (nature). Protagoras is often placed within this discourse as emphasizing the human, conventional basis of many norms:
- Laws and institutions are understood as products of human agreement.
- Ethical and political values are embedded in social practices, not fixed in nature.
Some interpreters see him as a conventionalist, treating nomoi as contingent yet binding within a community. Others argue that he recognized natural constraints—for example, human vulnerability and mutual dependence—as background conditions shaping viable conventions.
10.3 The Myth of Political Origins
In Plato’s Protagoras, the sophist recounts a myth describing how humans, initially vulnerable, receive technical skills from Prometheus but lack political art. Zeus then grants them aidos (respect) and dikē (justice) so that they can live together in cities. Scholars disagree on how far this myth reflects genuine Protagorean ideas, but many see in it:
- An account of political virtues as widely distributed capacities necessary for social survival.
- A justification of democratic participation, since everyone shares in the basic political sense.
- A view of law and punishment as instruments to maintain communal cohesion.
Whether or not this narrative is Protagoras’ own, it aligns with a perspective that grounds politics in shared human needs and mutual protection.
10.4 Law, Punishment, and Reform
Protagoras’ role in drafting laws for Thurii (if historical) would illustrate his belief that law is a human craft open to rational design and improvement. Even without firm evidence of this activity, his emphasis on education suggests that:
- Laws are tools for shaping character and behavior.
- Punishment aims at correction and deterrence, not mere retribution.
- Political communities can revise their nomoi in light of experience and argument.
This outlook is sometimes seen as an early form of constructivism about political order: institutions are justified insofar as they effectively promote collective flourishing.
10.5 Position in the Nomos–Physis Spectrum
Within the broader sophistic movement, some figures (e.g., Antiphon, Callicles as portrayed by Plato) stress sharp conflicts between natural advantage and conventional justice. Protagoras, by contrast, is often interpreted as:
- Less radical: acknowledging convention’s central role while not openly rejecting its authority.
- More integrative: viewing nomos as a rational response to natural human conditions.
However, because much of this comparison relies on Platonic representations, there remains substantial debate about how sharply Protagoras distinguished nomos from physis and whether he treated conventions as arbitrary, negotiable, or normatively weighty.
11. Religion, Agnosticism, and On the Gods
11.1 The Agnostic Fragment
The primary evidence for Protagoras’ religious views is the opening of On the Gods:
“Concerning the gods, I am unable to know whether they exist or do not exist, nor what form they have; for there are many obstacles to knowledge, the obscurity of the matter and the shortness of human life.”
— Protagoras, On the Gods (fr.), in Diogenes Laertius 9.51
This statement is commonly taken as an early articulation of agnosticism: a suspension of judgment about divine existence and nature, based on epistemic limitations rather than outright denial.
11.2 Scope and Motivation of Agnosticism
Interpretations differ regarding the reach of this agnosticism:
- Narrow reading: Protagoras doubts only the traditional anthropomorphic gods of Greek religion, leaving open more abstract forms of divinity.
- Broad reading: He highlights the in principle unknowability of any divine reality, given human cognitive constraints.
The motivations are likewise contested. Some emphasize a methodological stance (focusing inquiry on human affairs), while others see an implicit critique of mythological and oracular claims.
11.3 Relation to Relativism and Epistemology
Protagoras’ agnosticism dovetails with his broader epistemology:
- The gods, if they exist, lie beyond ordinary perception and shared experience, which for Protagoras may be the basis of knowable truth.
- Religious beliefs, therefore, fall into a domain where no reliable appearances are available, warranting suspension of judgment.
Some scholars argue that this position anticipates later skeptical arguments about the divine; others caution that we lack evidence for a fully developed skeptical program.
11.4 Social and Political Dimensions
Ancient reports that Protagoras faced an impiety charge and that his books were burned indicate the sensitivity of religious criticism in Athens. While the historicity of these events is uncertain, they point to tensions between:
- Traditional civic cults, seen as foundations of social order.
- Sophistic rational inquiry, which subjected inherited beliefs to examination.
Some interpreters suggest that Protagoras’ agnosticism may have been accompanied by a pragmatic acceptance of public rituals for their social utility, even if their theological basis was deemed unknowable. Others see him as part of a broader movement challenging the authority of mythic and poetic theology.
11.5 Protagoras and Greek Theology
In comparison with other thinkers:
| Thinker | Stance on the Divine (schematic) | Contrast with Protagoras |
|---|---|---|
| Xenophanes | Critiques anthropomorphic gods; posits a single supreme god. | Offers a positive theological doctrine, unlike Protagoras’ suspension. |
| Sophocles (tragedy) | Explores divine justice and fate through myth. | Works within mythic framework Protagoras questions epistemically. |
| Gorgias (as reported) | Argues paradoxically that nothing can be known, including gods. | Protagoras is more targeted: emphasizes limits specifically regarding gods. |
Thus, Protagoras stands out for grounding religious caution in explicitly epistemic reasons, making his agnosticism a significant, if sparsely documented, contribution to ancient reflection on religion.
12. Protagoras in Plato’s Dialogues
12.1 The Dialogue Protagoras
Plato’s Protagoras offers the most detailed literary portrait of the sophist. In it, Protagoras appears as:
- A celebrated educator, surrounded by followers.
- A confident defender of the teachability of virtue.
- A skilled practitioner of long speeches, myths, and interpretive exegesis.
Key elements often linked to Protagoras’ own thought include:
- The myth of Prometheus and the origins of political virtue, where all citizens share in basic political capacities.
- An argument that cities rightly allow all citizens to speak in political matters, unlike technical arts reserved to experts.
Scholars disagree on how literally these speeches reflect Protagoras’ own doctrines versus being Platonic constructions designed to explore Socratic themes.
12.2 Protagoras as Intellectual Rival
Within the dialogue, Socrates and Protagoras engage in methodological conflict:
| Aspect | Protagoras | Socrates |
|---|---|---|
| Preferred mode | Long, continuous speech | Short, question‑and‑answer dialectic |
| Conception of virtue | Multiple, socially embedded virtues | Presses toward unity and definition |
| Role of poetry | Central for moral education | Treated as needing critical interrogation |
Plato uses this contrast to dramatize competing models of education and philosophy. Some commentators view this as evidence that Protagoras represented a serious alternative to Socratic inquiry; others see him largely as a foil to highlight Socratic superiority.
12.3 The Measure Doctrine in Theaetetus
In Theaetetus, Plato presents a sustained examination of the Measure Doctrine, reconstructing Protagoras as holding that:
- Knowledge is perception.
- Each person is the measure for themselves of what is.
- Even the beliefs of non‑experts are, in some sense, true for them.
Socrates then develops self‑refutation arguments, suggesting that if some people believe Protagorean relativism is false, that belief would also be true‑for‑them, undermining the doctrine. Modern scholars debate whether these arguments engage Protagoras’ actual position or a Platonic caricature.
12.4 Protagoras in Other Dialogues
Protagoras is mentioned or alluded to in several other dialogues:
- In Cratylus, he is associated with certain views on language and naming, though details are vague.
- In Republic and Gorgias, unnamed sophists resembling Protagoras are sometimes invoked as representatives of relativistic and rhetorical approaches.
These references contribute to Plato’s broader narrative of sophistry as a rival to philosophy, but they rarely add precise doctrinal content.
12.5 Reliability and Interpretation
Scholars adopt varied stances on Platonic evidence:
- Maximalists treat Plato as a relatively reliable source who preserves genuine Protagorean ideas within a critical framework.
- Minimalists emphasize the dramatic and polemical nature of the dialogues, urging caution in projecting Platonic reconstructions back onto the historical Protagoras.
- Middle‑path approaches attempt to separate core doctrines (e.g., the Measure Doctrine, agnostic fragment) from Platonic elaboration, using comparative evidence from Aristotle and later doxography.
The resulting picture of Protagoras is therefore deeply shaped by interpretive judgments about the status of Plato’s portrayals.
13. Aristotle’s Critique and Later Ancient Reception
13.1 Aristotle on Protagorean Relativism
Aristotle frequently cites Protagoras as a paradigm of relativism about truth. In works such as the Metaphysics and On Sophistical Refutations, he attributes to Protagoras the thesis that:
- “What appears to each is true for each.”
- Contradictory statements can both be true, in a qualified sense.
Aristotle argues that such a view undermines:
- The principle of non‑contradiction, a cornerstone of his own logic.
- The distinction between appearance and reality.
- The possibility of philosophical inquiry, which seeks truths transcending individual perception.
His critique helped fix Protagoras in the ancient tradition as the leading exponent of problematic relativism.
13.2 Protagoras in Aristotle’s Rhetoric and Logic
In the Rhetoric, Aristotle classifies certain sophistic techniques, including the practice of making the weaker argument stronger, under the heading of eristic and apparent refutations. He also credits Protagoras with categorizing sentence types (e.g., questions, answers, commands), suggesting an early interest in linguistic analysis.
These references show that Aristotle recognized a degree of technical sophistication in Protagoras’ work, even as he criticized its philosophical implications.
13.3 Hellenistic and Roman Reception
Later schools engaged Protagoras in various ways:
| Tradition | Attitude toward Protagoras |
|---|---|
| Skeptics (e.g., Sextus Empiricus) | Used Protagorean relativism as one among several arguments highlighting the variability of appearances, but did not fully endorse it, preferring suspension of judgment over relativized truth. |
| Stoics | Opposed relativism, defending objective kataleptic impressions; they cited Protagoras among erroneous predecessors. |
| Epicureans | Acknowledged the reliability of senses but insisted on criteria of truth that allowed correction of false beliefs, distinguishing their view from Protagorean equal validity of appearances. |
| Roman rhetoricians (e.g., Cicero, Quintilian) | Referenced Protagoras as an important early teacher of rhetoric, sometimes ambivalently, recognizing his technical contributions while echoing moral criticisms. |
13.4 Biographical and Doxographical Traditions
Diogenes Laertius and other biographical compilers present Protagoras alongside other sophists, preserving:
- The agnostic fragment.
- Anecdotes about his impiety trial and shipwreck.
- Maxims about antilogies and rhetorical prowess.
These later accounts are valued for preserving fragments but are also shaped by moralizing and anecdotal tendencies, requiring careful critical handling.
13.5 Late Antique and Early Christian Views
In late antiquity, Protagoras’ name often appears in lists of unbelievers or impious philosophers. Early Christian apologists sometimes cite him as an emblem of:
- Human‑centered wisdom opposed to divine revelation.
- The dangers of relativism and skeptical doubt about the gods.
At the same time, his methodological focus on human affairs resonated with certain humanistic strands of later thought. Thus, even in polemical contexts, Protagoras helped define enduring debates about reason, faith, and the status of human perspectives.
14. Modern Interpretations of Protagorean Relativism
14.1 From Enlightenment to 19th Century
Early modern and Enlightenment thinkers rediscovered Protagoras mainly through Platonic and doxographical lenses. He was variously:
- Praised as a precursor of rational critique of religion and tradition.
- Condemned as an originator of skeptical and relativist excesses.
In the 19th century, historians of philosophy such as Hegel and Zeller integrated Protagoras into grand narratives: Hegel viewed sophistry as a necessary stage in the development of subjective freedom, while Zeller emphasized the epistemological relativism implied by the Measure Doctrine.
14.2 Analytic Reconstructions
In 20th‑century analytic philosophy, Protagoras became a touchstone for discussions of relativism and self‑refutation. Influential lines of interpretation include:
- Global relativism: Reading the Measure Doctrine as applying to all propositions, leading to familiar self‑refutation arguments (if some believe relativism false, that belief is also true‑for‑them).
- Restricted relativism: Limiting the doctrine to perceptual or evaluative statements, thereby avoiding some logical difficulties.
Formal semantic models have been developed to capture truth‑relative‑to‑a‑judge or context, with Protagoras often cited as an early intuitive source of such ideas.
14.3 Pragmatist and Contextualist Readings
Some modern scholars, influenced by American pragmatism and contextualism, reinterpret Protagoras less as a skeptic than as a pragmatist avant la lettre:
- Truth is tied to usefulness and success in human practices.
- Different contexts generate different standards of justification.
- Education aims at improving beliefs and practices, not discovering metaphysical absolutes.
On this view, the Measure Doctrine underscores the practical orientation of cognition rather than asserting that all opinions are equally good.
14.4 Communal vs. Individual Relativism
A major debate concerns whether Protagoras’ relativism is:
| Type | Description | Proponents |
|---|---|---|
| Individual relativism | Truth is relative to each person’s private appearances and beliefs. | Interpreters closely following Plato’s Theaetetus. |
| Communal relativism | Truth is relative to linguistic and cultural communities, their nomoi and shared practices. | Scholars emphasizing the political and educational context of sophistry. |
Communal readings seek to make Protagoras more philosophically robust and socially oriented, though critics argue that textual evidence for this shift from individual to communal “measure” is limited.
14.5 Ethical and Political Implications
Contemporary theorists of liberalism, multiculturalism, and discourse ethics sometimes invoke Protagoras as a historical reference point when exploring:
- The possibility of value pluralism without moral nihilism.
- The role of public reasoning and rhetoric in legitimizing norms.
- The tension between universal human rights claims and cultural relativism.
Interpretations vary widely: some see Protagoras as an early champion of tolerance and democratic deliberation; others stress the potential for manipulation and power inherent in his focus on persuasion.
14.6 Ongoing Scholarly Disagreements
Current scholarship remains divided on key questions:
- The extent and domain of Protagoras’ relativism.
- Whether he offered a coherent epistemological theory or primarily a pedagogical stance.
- How his views relate to contemporary debates in metaethics, epistemology, and political theory.
Despite these disagreements, modern interpretations converge in recognizing Protagoras as a central figure in the history of relativistic thought, whose doctrines continue to provoke reflection on the nature and limits of human perspectives.
15. Legacy and Historical Significance
15.1 Paradigmatic Sophist
Protagoras has long served as the paradigmatic sophist in both ancient and modern narratives. Through Plato’s dialogues and Aristotelian critiques, he came to symbolize:
- Professionalized wisdom offered for pay.
- Emphasis on rhetoric and argument over metaphysical speculation.
- A human‑centered, this‑worldly orientation in philosophy.
This image shaped subsequent attitudes toward sophistry—alternately as a dangerous corruption of youth and as a necessary component of civic education.
15.2 Contributions to Epistemology and Relativism
The Measure Doctrine established Protagoras as a foundational figure in debates about:
- The relationship between perception, belief, and truth.
- The relativity of knowledge to subjects or communities.
- The possibility and limits of objective standards.
Later epistemological discussions—from ancient Skeptics to modern analytic philosophers—continue to engage with Protagorean themes, particularly concerning self‑refutation and indexed truth.
15.3 Influence on Ethics, Politics, and Law
Protagoras’ insistence that virtue is teachable and his focus on civic aretē contributed to enduring questions about:
- The role of education in forming citizens.
- The human construction of laws and institutions.
- The justification of democratic participation as grounded in widely shared capacities.
His reputed role in drafting laws for Thurii, whether fully historical or not, reinforced the idea that political order is a matter of deliberate design rather than immutable tradition.
15.4 Impact on Religious and Secular Thought
The agnostic stance of On the Gods influenced later treatments of religion and skepticism. Protagoras is frequently cited in histories of:
- Secularization, as an early example of subjecting theological claims to rational scrutiny.
- Agnostic and skeptical traditions, highlighting human cognitive limits regarding the divine.
Even when condemned by religious authors, he functioned as a reference point for delineating the boundaries between faith and philosophical inquiry.
15.5 Reception in Intellectual History
Across centuries, Protagoras has been variously:
| Period | Dominant Image |
|---|---|
| Classical and Hellenistic | Relativist sophist, foil for philosophers like Plato and Aristotle. |
| Late Antique / Early Christian | Symbol of impiety and human presumption. |
| Renaissance / Enlightenment | For some, early rationalist critic of tradition; for others, emblem of skepticism. |
| Modern academic philosophy | Case study in relativism, rhetoric, and the social dimensions of knowledge. |
These shifting portrayals illustrate how Protagoras’ thought has been continuously reinterpreted in light of changing philosophical, religious, and political concerns.
15.6 Enduring Questions
Protagoras’ legacy endures less in the form of a systematic doctrine and more as a set of provocative questions:
- Are truth and value human‑dependent, and if so, in what sense?
- How should societies balance persuasion and truth, education and power?
- What are the limits of human knowledge, especially regarding ultimate metaphysical or religious claims?
By foregrounding human perspectives, practices, and institutions as the primary arena of inquiry, Protagoras helped to define a trajectory of thought in which philosophy grapples with contingency, pluralism, and the constructed character of social life—issues that remain central to contemporary reflection.
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@online{philopedia_protagoras_of_abdera,
title = {Protagoras of Abdera},
author = {Philopedia},
year = {2025},
url = {https://philopedia.com/philosophers/protagoras-of-abdera/},
urldate = {December 10, 2025}
}Note: This entry was last updated on 2025-12-08. For the most current version, always check the online entry.
Study Guide
intermediateThe biography assumes some familiarity with ancient Greek history and basic philosophical vocabulary. The ideas of epistemic relativism, agnosticism, and the nomos–physis debate are conceptually demanding, but the article explains them clearly enough for motivated readers who are beyond complete beginner level.
- Basic ancient Greek history (5th century BCE) — Understanding the political setting of democratic Athens, the Persian and Peloponnesian Wars, and the role of the polis helps make sense of why rhetoric and civic virtue were so important in Protagoras’ career.
- Introductory concepts of pre-Socratic philosophy — Knowing that earlier thinkers focused on nature (physis), cosmology, and the shift toward human affairs sets the stage for seeing how Protagoras both continues and departs from pre-Socratic concerns.
- Familiarity with Plato and Socrates (at a basic level) — Most of what we know about Protagoras comes through Plato’s dialogues and Aristotelian reports; some sense of who Socrates and Plato are helps you evaluate how Protagoras is portrayed and criticized.
- Very basic epistemology vocabulary (truth, knowledge, belief, perception) — Protagoras’ Measure Doctrine and epistemic relativism can otherwise feel opaque; minimal epistemological vocabulary makes his views and Plato’s objections much easier to follow.
- Overview of Ancient Greek Philosophy — Gives you a map of major figures and movements so you can place Protagoras among the pre-Socratics, sophists, and classical philosophers.
- Socrates of Athens — Helps you see how Protagoras functions as a foil for Socrates in Plato’s dialogues and clarifies the differences between Socratic philosophy and sophistic education.
- Plato of Athens — Since Plato is the main source for Protagoras’ doctrines, understanding Plato’s aims and style (especially his use of dialogues and dramatic framing) will help you read his portrayal of Protagoras critically.
- 1
Get oriented to who Protagoras is and why he matters.
Resource: Section 1. Introduction
⏱ 20–30 minutes
- 2
Learn the basic story of his life, context, and sources.
Resource: Sections 2–3 (Life and Historical Context; Sources and Historiographical Problems)
⏱ 40–50 minutes
- 3
Understand Protagoras as a working sophist and educator.
Resource: Sections 4–5 (Intellectual Development and Career as a Sophist; Major Works and Fragments)
⏱ 40–50 minutes
- 4
Study his core doctrines about truth, knowledge, and virtue.
Resource: Sections 6–9 (Measure Doctrine and Relativism; Epistemology; Ethics; Rhetoric and Antilogies)
⏱ 1.5–2 hours
- 5
Explore his political, legal, and religious views in context.
Resource: Sections 10–11 (Politics, Law, and Nomos–Physis; Religion, Agnosticism, and On the Gods)
⏱ 60–75 minutes
- 6
Examine how later thinkers read and transform Protagoras.
Resource: Sections 12–15 (Protagoras in Plato’s Dialogues; Aristotle’s Critique; Modern Interpretations; Legacy and Historical Significance)
⏱ 1.5–2 hours
Sophist (σοφιστής, sophistēs)
A professional teacher in classical Greece who offered instruction in rhetoric, argumentation, and practical wisdom for a fee, usually aimed at success in public and legal life rather than purely speculative theory.
Why essential: Understanding what sophists were, and how they differed from philosophers like Socrates and Plato, is crucial for grasping Protagoras’ social role, the criticisms he faced, and why his teachings were controversial.
Measure Doctrine (“man is the measure of all things”)
Protagoras’ thesis that human beings are the standard (metron) for what is and is not; that is, what appears or seems true to a person (or community) is true-for that subject, making cognition and value relative to human perspectives.
Why essential: This is the core of Protagoras’ epistemology and relativism; nearly all later discussion—ancient and modern—about his thought turns on how to interpret and assess this doctrine.
Relativism / Epistemic relativism
The view that truth or knowledge is not absolute but depends on the standpoint of an individual or community; for Protagoras, whatever appears to someone is true-for that perceiver, so conflicting appearances can both be true in a relative sense.
Why essential: To understand Plato’s and Aristotle’s critiques, Protagoras’ role in the history of philosophy, and modern debates about self-refuting relativism, you must first have a clear grip on what relativism claims in his case.
Antilogia (ἀντιλογία) and logoi (λόγοι)
Antilogia is the technique of setting opposing arguments (logoi) against each other on any given issue, both as a method of training in rhetoric and as a reflection of the fact that many matters admit plausible reasons on both sides.
Why essential: This concept illuminates Protagoras’ teaching methods, his reputation for ‘making the weaker argument stronger,’ and the connection between his pedagogical practices and his theoretical commitments about the plurality of perspectives.
Aretē (ἀρετή) and the teachability of virtue
Aretē means excellence or virtue, especially civic and practical excellence; Protagoras maintained that such virtue can be taught through systematic education in speech, judgment, and civic skills rather than relying solely on innate talent or divine favor.
Why essential: Protagoras’ self-presentation as a teacher of virtue is central to his identity as a sophist and to Plato’s engagement with him; it also raises important questions about moral education and responsibility within a relativistic framework.
Nomos (νόμος) vs. Physis (φύσις)
Nomos refers to law, custom, and convention created by humans; physis refers to nature or the inherent order of things. In the 5th century BCE, this contrast framed debates about whether ethical and political norms are conventional or grounded in nature.
Why essential: Protagoras’ emphasis on human-made norms, lawmaking, and democratic participation makes sense only against this background; his political thought is often read as a sophisticated conventionalism that still takes human nature and vulnerability seriously.
Agnosticism in On the Gods
Protagoras’ stance that he cannot know whether the gods exist or do not exist, nor what they are like, because of the obscurity of the subject and the limitations of human life—an early, explicit suspension of judgment about divine matters.
Why essential: This fragment is key to understanding why Protagoras was accused of impiety, how his epistemology extends to religious questions, and why later traditions treat him as an important figure in the history of skepticism and secular thought.
Attic Enlightenment and Protagoreanism
A modern label for the 5th‑century Athenian movement of critical, rational inquiry into law, custom, and belief, in which figures like Protagoras helped professionalize education and foreground human-centered criteria for truth and value (sometimes called Protagoreanism).
Why essential: Seeing Protagoras within this broader cultural and intellectual movement helps explain his influence on democratic Athens, his conflicts with traditional religion, and his later reception as both a corrosive relativist and a pioneering critic of dogma.
Protagoras claimed that all opinions are equally good and that there is no basis at all to prefer one belief over another.
While he held that every appearance is true-for the one who has it, the evidence suggests he distinguished between better and worse arguments in terms of practical outcomes and civic benefit; his educational practice presupposes that some ways of thinking and arguing improve individuals and cities.
Source of confusion: Plato’s polemical arguments in the Theaetetus often present a ‘maximal’ relativism that is easier to refute; this can be mistaken for Protagoras’ own, more nuanced position.
Protagoras was primarily a cynical trickster who just taught people to manipulate juries and assemblies for money.
Although he did charge fees and taught persuasive techniques, the article shows him as a serious thinker about knowledge, virtue, law, and religion, and as someone entrusted (traditionally) with drafting laws for Thurii, which indicates a degree of public trust and practical wisdom.
Source of confusion: Comic playwrights and philosophical critics (Aristophanes, Plato, Aristotle) caricatured sophists as morally dubious, and these stereotypes have often been uncritically repeated.
The agnostic statement in On the Gods means Protagoras was simply an atheist denying the existence of any gods.
The fragment explicitly suspends judgment: he says he is unable to know whether the gods exist or do not exist, emphasizing epistemic limits rather than a dogmatic denial of divinity.
Source of confusion: Later religious polemics often lumped agnosticism and atheism together as ‘impiety,’ and some modern summaries oversimplify his nuanced epistemic stance.
Everything we read in Plato’s dialogue Protagoras must be an accurate transcript of Protagoras’ own views and style.
The article stresses that Plato’s dialogues are dramatic and philosophical constructions; although they probably preserve genuine Protagorean themes, Plato shapes speeches, myths, and arguments to serve his own purposes and to contrast sophistic and Socratic methods.
Source of confusion: Students often overlook the literary and polemical nature of the dialogues and treat them as straightforward historical sources.
Relativism for Protagoras is only about individual, private perceptions and has nothing to do with communities or shared norms.
Some interpretations, supported by his focus on nomos, democratic debate, and education, see his relativism as at least partly communal—tied to shared practices and civic standards—even if Plato emphasizes the individualist reading in Theaetetus.
Source of confusion: Relying exclusively on Theaetetus encourages an individualistic reading; the political and educational dimensions in other testimonies suggest a more complex picture.
How does Protagoras’ role as a paid sophist in democratic Athens shape the kinds of philosophical questions he asks about knowledge, virtue, and law?
Hints: Connect Section 2 (historical context) with Sections 4 and 9 on his career and pedagogy. Consider how the needs of juries, assemblies, and ambitious citizens might influence his focus on rhetoric, civic aretē, and relativism about appearances.
In what sense can the Measure Doctrine be understood as a claim about ‘truth-for’ rather than ‘truth simpliciter’? Does this help Protagoras avoid some of Plato’s self-refutation objections?
Hints: Look at Sections 6 and 7. Try to formalize what it means for a statement to be true-for-S. Then examine Socrates’ objections in the Theaetetus: are they targeting global, unindexed truth, or do they still bite if truth is indexed to subjects or communities?
Can Protagoras coherently claim to improve his students’ virtue and judgment if he is a relativist about truth and value? On what standards could ‘improvement’ be assessed?
Hints: Draw on Sections 6, 7, and 8. Consider pragmatic and political criteria (e.g., better outcomes for the city, more stable social order, personal success). Are these enough to make sense of improvement without appealing to absolute moral standards?
Compare Protagoras’ agnosticism in On the Gods with his general epistemological stance. Is his suspension of judgment about the gods just a special case of his overall view about the limits of human knowledge, or does it go further?
Hints: Use Section 11 together with Sections 6–7. Ask: what makes the gods a particularly hard case for knowledge on a Protagorean view? How does the lack of shared, stable appearances in religious matters differ from ordinary perceptual cases?
To what extent does the myth of Prometheus and the origins of political virtue in Plato’s Protagoras (Section 10) likely reflect Protagoras’ own political theory rather than Platonic invention?
Hints: Review Sections 3, 10, and 12. Consider what we know independently about Protagoras’ views on education, democracy, and nomos. Then ask which elements of the myth (e.g., universal distribution of political virtue, function of punishment) fit well with those views and which might be Platonic dramatization.
Is it more plausible to interpret Protagoras as an individual relativist (truth relative to each person) or as a communal relativist (truth relative to shared norms and practices)? What textual evidence from the article supports your view?
Hints: Focus on Sections 6, 7, 10, and 14. List passages that stress individual perception and those that stress nomos, lawmaking, and communal standards. Weigh how much of our evidence is mediated by Plato versus other sources like Aristotle and Diogenes Laertius.
How has the image of Protagoras changed from antiquity through modern philosophy, and what does this tell us about the shifting concerns of later interpreters?
Hints: Consult Sections 13–15. Track three or four stages: Plato/Aristotle, Hellenistic schools, early Christian authors, and modern historians or analytic philosophers. For each, ask: why did they focus on certain aspects of Protagoras (impiety, relativism, rhetoric, secularism)?